What does “Daily Recommended Intake (RDA)” Really Mean?

Today I saw an ad for an orange “fruit-flavored beverage” with “10% real juice!” – as if this figure was something to brag about! But what made me stop short was the claim that this fine product contained “100% of your daily vitamin C requirement.” Now how is it that what is basically nothing more than a dyed sugar water, laden with chemicals, only one tenth of which is made up of anything natural, claim to contain 100% of your daily vitamin C needs?

According to the label, the drink contains 90mg of vitamin C. A quick check of the “Daily Recommended Intake” (DRI) chart developed and revised over many decades, and under many aliases, by Health Canada, should find what we’re looking for. It does indeed show that 90mg is the Recommended Dietary Allowance, or RDA, of vitamin C for the average teen or adult for one day. But what does this number actually mean?The RDAs were originally developed during World War II in order to analyze the diets of groups of people (specifically soldiers on the front lines). What they were not created to address were the nutritional needs of individuals. And how could they be, considering each individual has differing nutrient needs based on body chemistry, environment and lifestyle? As Michael Murray and Joseph Pizzorno, both Naturopathic Doctors and authors of the Encyclopedia of Natural Medicine, write “The RDAs were designed to serve as the basis for evaluating the adequacy of diets of groups of people, not individuals. Individuals simply vary too widely in their nutritional requirements”.

And even if we look at the Health Canada DRI charts we see that they have indicated that smokers need tor raise their vitamin C intake by 35mg above the RDA. This is a start, but what about all the other nutrients that have been shown to be negatively affected by smoking? What about other lifestyle factors like alcohol, chemical exposure or heavy metals? What about other ingredients in foods such as dyes, preservatives or flavourings and their affects on vitamin requirements? What about the difference between those who lead active versus sedentary lifestyles and how this affects their needs? The list could go on.

But quite aside from this point, there is the idea put forward by nutritionists and naturopaths that the RDAs are simply too low for even the average healthy person. Again, Murray and Pizzorno write “A tremendous amount of scientific research indicates that the optimal level for many nutrients, especially the antioxidant nutrients, such as vitamins C and E, beta-carotene, and selenium, may be much higher than their current RDAs.” They go on, “the RDAs […] do not define optimal intake for an individual.” Do you really want to pin your daily intake of a vital nutrient on what is considered adequate for the average individual to prevent deficiency disease? Or would you rather get the optimal amount of that nutrient for you to personally thrive?

The research has shown the quantity of vitamin C needed by different individuals is incredibly variable. During nutritional therapy, some nutritionists recommend finding out your tolerance for vitamin C intake by taking 1000mg orally per half-hour until loose stools develop, (the first sign that one has reached their tolerance level), and then to cut back from there. It is believed that this is the level at which the vitamin is best able to fight disease. Mind you, this is a massive amount of vitamin C and is really only taken for therapeutic reasons, not as a daily dosage. However, we can see that right off the bat we are dealing with numbers in the thousands of milligrams. Compare this to the suggested 90mg.

This being said, I’m a firm believer in the idea that, if you’re eating a diet of whole foods, laying off the processed crap and eating your fruits and veggies, you shouldn’t need to be counting anything – not calories, not grams of fibre, not milligrams of vitamin C. I’m not suggesting you avoid taking supplements, particularly if you have a condition or lifestyle that warrants it. But you should question whether this processed food, or even supplement pill, is really giving you everything you need. It’s my belief that if you’re reaching for an orange instead of an orange flavoured fruit beverage you’re going to be a lot better off. Which one do you think they’re serving in your child’s school?

A Review by The Editor:

Good points! Vitamins are not found in nature as separated – dissected from the food they are PART of. We need the WHOLE food – including the fiber.

The crap in food needs to be criticized….not just some stat of RDA. Also should be the pesticides used and the pollution to transport that orange or whatever. Also the working conditions/labor policy.

We need to eat local organically grown whole foods. Cabbage has great amounts of vitamin C! And, as with all cabbage family plants, are better for us when fermented – as in kimchi and sauerkraut. Going back to traditional preps – I mean going forward. Who cares. Just try making them…easy and yummy.

As for Health Canada –well, I’ve learned to take their “recommendations” with a grain of Kosher Salt. Back in the 90’s, when they first started to worry about Canada’s weight problem, they seemed to imply you could eat unlimited amounts of ANY food loaded with “fiber” and free of Demon Fat. Yes, you could really slim down on a pot or two of Meatless Chili, and a large pan of Veggie Lasagna with soy cheese….